Arrays of mirrors of the heliostat type are being used to direct solar light to a receiver. To make utilization of solar energy practical, it is necessary that a large number of heliostats are used. Thus, a large number of mirrors surfaces must be constructed, arrayed, cleaned, protected from the elements and eventually replaced.
Mirror surfaces are expensive to construct to the desired configuration and the surfaces are oftentimes subject to destruction by the elements in a relatively short period of time. Mirror surfaces that are not subject to destruction in short periods of time are often prohibitively expensive and are required to be made from exotic and expensive materials. Yet even using these materials, the mirror surfaces have to be cleaned often because of the elements. Where the mirror surfaces may cover an area in the order of several acres, the task of maintaining the mirror surfaces in good condition, cleaning their surfaces and replacing the surfaces from time to time becomes prohibitively expensive.
Because of these limitations and because of the low power of solar energy, oftentimes the operational expenses involved in converting solar energy into usable power are so large that solar energy becomes a hopelessly non-competitive power source. It is therefore an advantage to have a renewable surface heliostat type solar mirror in which the surfaces can be kept reasonably clean and selectively replaced, in a manner that is less expensive than constructing and replacing expensive mirror surfaces and keeping the mirror surfaces clean.